Rotary-rigid orthopaedic rod

ABSTRACT

Apparatus and method for repairing a fractured bone. The apparatus and methods may involve an intramedullary rod. The rod may include a first elongated member and a second elongated member. Each of the first and second elongated members may be configured to bend in a first direction and to resist bending in a second direction. The first and second elongated members may be arranged such that; (1) the rod is bendable when the first direction of the first elongated member is aligned with the first direction of the second elongated member; and (2) the rod is rigid when the first direction of the first elongated member is aligned with the second direction of the second elongated member. Some embodiments may include rods that have sections that may be configured to be curved and rigid.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a nonprovisional of U.S. Provisional ApplicationsNo. 61/295,244, filed on Jan. 15, 2010, which is hereby incorporated byreference in its entirety.

FIELD OF TECHNOLOGY

Aspects of the disclosure relate to providing apparatus and methods forrepairing bone fractures. In particular, the disclosure relates toapparatus and methods for repairing and/or stabilizing bone fracturesutilizing a device that is inserted into a bone.

BACKGROUND OF THE INVENTION

Currently, there are many known ways to treat long bone fractures.Common fracture treatments include: (1) nonsurgical immobilization; (2)osteosuture and tension band technologies; (3) percutaneous fixation(e.g., using pins, wires, screws Etc.); (4) rigid intramedullary nailing(e.g., using a large rod and external screws); (5) flexible plateosteosynthesis (e.g., a “load sharing” suture); (6) arthroplasty (e.g.,using a prosthesis); (7) plating and other indication specifictechniques. Severe fractures that meet certain clinical criteria mayrequire surgical repair rather than non-surgical immobilization.

The midshaft of an elongated or long bone is typically classified as thediaphysis.

In general, fracture fixation may provide longitudinal (along the longaxis of the bone), transverse (across the long axis of the bone), androtational (about the long axis of the bone) stability. Fracturefixation may also preserve normal biologic and healing function.

There are two primary categories for surgical fixation: a device that iswithin the skin (internal fixation); and a device that extends out ofthe skin (external fixation). There are two common types of internalfixation approaches for long bone surgery (a) a plate that is screwed tothe outside of the bone; or (b) a rod that goes down the center of thebone.

Plates are characterized by relatively invasive surgery, support offractured bone segments from one side outside of bone, and screws thatanchor into the plate and through the entire bone. Successful repair isdependent on fracture pattern, bone quality, and patient tolerance of aforeign body, among other factors. Plates may not properly address thealignment and stability requirements for periarticular and intrarticularfractures.

Intramedullary rods or nails, such as those used in mid shafttreatments, are often used instead of plates and screws to reducesoft-tissue trauma and complications. Typically, an intramedullary rodor nail is fixed in diameter and is introduced into the medullary canalthrough an incision in the articular surface.

Flexible intramedullary rod-like solutions utilize structures that canbe flexed for insertion into the medullary cavity through a diaphysealor metaphyseal access site. The structures may then be made rigid insidethe intramedullary cavity. The structures are often reinforced withpolymers or cements. Making the structures rigid is important forsurgical fixation.

It would be desirable, therefore, to provide apparatus and methods forbone fracture alignment and stabilization.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the invention will be apparent uponconsideration of the following detailed description, taken inconjunction with the accompanying drawings, in which like referencecharacters refer to like parts throughout, and in which:

FIG. 1 shows illustrative apparatus in accordance with principles of theinvention;

FIG. 2 shows a partial cross-section taken along lines 2-2 (shown inFIG. 1)

FIG. 3 shows a perspective view, taken approximately along lines 3-3, ofa portion of the apparatus shown in FIG. 1, when the apparatus is in afirst configuration;

FIG. 4 shows a partial cross-section taken along the lines 4-4 (shown inFIG. 3).

FIG. 5 shows a partial cross-section taken along the lines 5-5 (shown inFIG. 3).

FIG. 6 shows the view of FIG. 3 when the apparatus is in a secondconfiguration.

FIG. 7 shows a perspective view of a portion of the apparatus shown inFIG. 1.

FIG. 8 shows the apparatus of FIG. 1, along with other apparatus and abone;

FIG. 9 shows a partial cross-sectional view of a portion of theapparatus shown in FIG. 1 taken along lines 9-9 (shown in FIG. 1).

FIG. 10 shows a partial cross-sectional view of a portion of theapparatus shown in FIG. 1 taken along lines 10-10 (shown in FIG. 1).

FIG. 11 shows a partial cross-sectional view taken along lines 11-11(shown in FIG. 1) when the apparatus is in a configuration that isdifferent from that shown in FIG. 1.

FIG. 12 shows the apparatus of FIG. 1, along with other apparatus and adifferent bone.

FIG. 13 shows a flat model representation of features of apparatus suchas that shown in FIG. 1.

FIG. 14 shows schematic apparatus in accordance with Lhe principles ofthe invention.

FIG. 15 shows other schematic apparatus in accordance with theprinciples of the invention.

FIG. 16 shows other apparatus in accordance with the principles of theinvention.

FIG. 17 shows yet other apparatus in accordance with the principles ofthe invention.

FIG. 18 shows still other apparatus in accordance with the principles ofthe invention.

FIG. 19 shows a portion of the apparatus shown in FIG. 18.

FIG. 20 shows a partial cross-sectional view, taken along lines 20-20(shown in FIG. 19), of the apparatus shown in FIG. 19.

FIG. 21 shows a pattern that may be used to manufacture apparatus inaccordance with the principles of the invention.

FIG. 22 shows illustrative steps of a process in accordance with theprinciples of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Apparatus and method for repairing a fractured bone are provided. Theapparatus and methods may involve an intramedullary rod. The rod mayinclude a first elongated member and a second elongated member. Anelongated member may be referred to herein as a sleeve. Each of thefirst and second elongated members may be configured to bend in a firstdirection and to resist bending in a second direction. The first andsecond elongated members may be arranged such that: (1) the rod isbendable when the first direction of the first elongated member isaligned with the first direction of the second elongated member; and (2)the rod is rigid when the first direction of the first elongated memberis aligned with the second direction of the second elongated member.

An elongated member may be an elongated tubular member. The firstelongated member may be disposed coaxially within the second elongatedmember. The inner member may have a length that is longer, shorter orsubstantially the same as the length of outer member. The innerelongated member may include a central longitudinal void or may besolid, essentially solid or porous. The inner elongated member mayrotate freely within an outer elongated member.

The elongated member may include implantable materials such as metals,polymers, composites and any other suitable materials.

The first direction may correspond to an arrangement of stress-relieffeatures. The stress-relief features may include slots that arelongitudinally spaced from each other. The slots may be stress-reliefslots. The slots may be configured to provide tension relief. The slotsmay be configured to provide compression relief. Slots may belongitudinally separated by ribs. The ribs and/or slots may becircumferentially separated by one or more longitudinal members.

Slots may be formed by different cut patterns/arrangements in anelongated member. The different patterns/arrangements may providedifferent bending properties. Slots, holes or other void features may beprovided by laser cutting or any other suitable method.

Different materials may be used to construct an elongated member, anddifferent materials may provioe different bending properties. Propertiesof features of an elongated member such as angular separation,thickness, height, separation, ratio of height to separation,composition or material, structure or microstructure or other suitableproperties may provide different bending properties. The properties ofan elongated member may vary along the longitudinal axis of theelongated member.

The stress-relief features may include any suitable microstructure, suchas one or more of the following: sinters, kerfs, cuts, cells,perforations, holes, patterns, helical paths, cells, slots, tapers,angled cuts and any other suitable structure or microstructure.

The first direction of an elongated member may correspond to: (a) afirst arrangement of slots that are longitudinally spaced from eachother for tension relief; and (b) a second arrangement of slots that arelongitudinally spaced from each other to provide compression relief. Thefirst and second arrangements of slots may be spaced circumferentiallyapart from each other on one of the elongated members.

The apparatus may include a delivery cannula. The delivery cannula mayprovide a curved entry path into an intramedullary channel through anaccess hole in a bone.

The apparatus may include a control shaft. The control shaft may extendthrough the delivery cannula. The control shaft may manipulate one ormore elongated members. The control shaft may be removed after elongatedmembers are rotationally locked or rod is locked to bone. Anchors maylock an elongated member and attach rod to bone.

The intramedullary rod may include adjustment flanges. The adjustmentsflanges may be used to adjust the first and second elongated membersrelative to each other in a circumferential direction.

An elongated member may include an anchor-receiving feature. Theanchor-receiving feature may include holes or voids in the elongatedmember. The anchor-receiving feature may be tapered, may includemesh-like cells that are configured to engage an anchoring device or mayhave different sizes, parameters or features. The spacing between theanchor-receiving features and the size and shape of the anchor-receivingfeatures may be configured to cooperate with one or more types ofdifferent anchors. The anchor-receiving features may be may be sized asto interact/cooperate with each other. The anchor-receiving features maybe sized or shaped differently to reduce or relieve angular stressbetween an inner and outer elongated member.

The first and second elongated members may include, respectively, afirst anchor-receiving feature and a second anchor-receiving feature.The first and second elongated members may be configured to bepositioned relative to each other such that the first anchor-receivingfeature and the second anchor-receiving feature are positioned toreceive the same anchor. The first and second anchor-receiving featuresmay be distal the first and second arrangements of slots.

The first and second elongated members may include, respectively, athird anchor-receiving feature and a fourth anchor-receiving feature.The first and second elongated members may be configured to bepositioned relative to each other such that the third anchor-receivingfeature and the fourth anchor-receiving feature are positioned toreceive the same anchor. The third and fourth anchor receiving featuresmay be proximal the first and second arrangements of slots.

Anchors may penetrate one or more of the anchor-receiving features andsecure one elongated member relative to another elongated member.Anchors may prevent the elongated members from rotating out ofalignment. Anchors may penetrate bone and may used to apply tensionacross a bone fracture.

An elongated member may include one or more elastic sections. An elasticsection may apply a compressive or a tensile force between proximal anddistal anchors of the elongated member. The tensile force may be appliedacross the bone fracture by anchoring the elongated member such that theelastic section is in compression. The compressive force may be appliedacross the bone fracture by anchoring the elongated member such that theelastic section in tension.

The rod may include a locking mechanism. The locking mechanism mayinclude: (a) a first attachment to the first elongated member; (b) asecond attachment to the second elongated member; and (c) a bridgingmember that is configured to prevent relative rotation about thelongitudinal axis of the first elongated member with respect to thesecond elongated member. One or both of the first and second attachmentsmay be threaded.

The locking mechanism may include one or more of a threaded nut, a sectscrew, a cotter pin, a crimp, a swage, a morse taper and any othersuitable mechanical interface or mechanism.

In some embodiments, the first elongated member may include afixed-curve portion. The fixed-curve portion may have a fixed curve. Thefixed curve may define a fixed-curve plane. The fixed curve plane mayinclude the second direction of the first elongated member.

In some embodiments, the first elongated member may include a firstfixed-curve portion and the second elongated member may include a secondfixed-curve portion. The second fixed-curve portion may have a secondfixed curve. The second fixed curve may define at second fixed-curveplane. The second fixed curve plane may include the second direction ofthe second elongated member.

In some embodiments, the intermedullary rod may be fixed in a rigidstate that includes one or more straight sections and one or more curvedsections. In some embodiments, rotation of a first elongated memberrelative to a second elongated member may cause rod to become rigid in acurved or bent configuration to provide mechanical support to differentportions of a bone.

A fixed-curve portion may include a first segment and a second segment.A segment may be a compound segment. The second segment may be directlyattached to the first segment. The first segment may include a firstrigid bend. The second segment may include a second rigid bend. When thefirst and second bends lie in the fixed-curve plane: (a) the fixed-curveportion may be resistant to bending in the fixed-curve plane; and (b)the fixed curve portion may be non-resistant to bending in a plane thatis different from the fixed-curve plane.

The first segment may be linked to the second segment by an articulatinglinkage. The articulating linkage may include a female linkage memberand/or a male linkage member. The first and second segments may beformed from a unitary body. The unitary body may be a tube.

The first elongated member may include a segment that has a first endthat includes a first linkage that has a first pivot axis. The firstlinkage may provide a connection to a first neighboring segment. Thesegment may have a second end that is spaced a distance apart from thefirst end. The second end may include a second linkage. The secondlinkage may include a second pivot axis. The second linkage may providea connection to a second neighboring segment. The distance may define alongitudinal axis. The distance may define a direction that may bereferred to as a longitudinal axis. The second pivot axis may beangularly offset, about the longitudinal axis, from the first pivotaxis.

The first pivot axis may define the first direction of the firstelongated member.

The second pivot axis may define the second direction of the firstelongated member.

The segment may include a first end that includes a first linkage. Thefirst linkage may have a first pivot axis. The first linkage may providea connection to a first neighboring segment. The segment may include asecond end. The second end may be spaced a distance apart from the firstend. The second end may include a second linkage. The second linkage mayhave a second pivot axis. The second pivot axis may provide a connectionto a second neighboring segment.

The distance may define a longitudinal axis. The distance may define adirection that may be referred to a longitudinal axis. The first andsecond pivot axes may define intersecting lines when the segment isviewed along a direction that is substantially normal to thelongitudinal axis.

The first pivot axis may define the first direction of the firstelongated member.

The second pivot axis may define the second direction of the firstelongated member.

The second pivot axis may be angularly offset, about the longitudinalaxis, from the first pivot axis.

A segment may include a segment body. The segment body may include oneor more implantable material such as metal, polymer, composite and anyother suitable material. The segment body may include one or more formssuch as a cylinder, a prism, a curve and any other suitable shape.

The segment may be one of a chain of segments. The chain of segments mayform all or a portion of the elongated member of the intermedullary rod.The segment chain may be placed inside an outer elongated member. Theouter member may be provided with stress relief features that aredistributed along the length and circumference of the member. A relativeorientation of the chain and the outer elongated member may allow therod to be oriented in a bendable or rigid orientation.

The rod may include a bone support extending from an end of the firstand/or second elongated members. The end may be a proximal or a distalend. The rod may include two bone supports. One of the bone supports mayextend from the first elongated member. The other may extend from thesecond elongated member.

The bone support may be fixed to one or more bone fragments. Fixation tobone may include using any suitable anchoring device.

In some embodiments, the rod may include an outer tubular member that isconfigured to bend about a first axis and an inner member disposedinside the outer tubular member. The inner member may include a segmentthat is configured to move: (a) relative to a first attached neighboringsegment, about a second axis; and (b) relative to a second attachedneighboring segment opposite the first attached neighboring segment,about a third axis.

The second axis may be substantially parallel to the first axis. Thethird axis may be substantially perpendicular to the first axis.

The inner member may be configured to rotate, relative to the outertubular member, from a first position in which the second axis isparallel to the first axis, and the rod is bendable, to a secondposition in which the third axis is substantially perpendicular to thefirst axis, and the rod is resistant to bending.

The segment may be configured to move relative to the first and secondneighboring segments by respective operation of first and secondarticulating linkages.

The segment, the first neighboring segment and the second neighboringsegment may be formed from a unitary body. The unitary body may be atube.

The methods may include a method for delivering an intramedullary rod toa bone. The method may include inserting a flexible intramedullary rodthrough an angled access hole into an intramedullary channel; andconfiguring the intramedullary rod in a rigid configuration by aligninga bending feature of a first sleeve with a non-bending feature of asecond sleeve.

The method may include drilling the angled access hole at an angle to alongitudinal axis of the bone. The method may include preparing anintramedullary space to receive the rod. The method may include aligningthe first and second sleeves to make the rod flexible. The method mayinclude inserting the rod into the intramedullary space. The method mayinclude rotating the first sleeve relative to the second sleeve to makethe rod inflexible. The method may include fixing a rotational offsetbetween the first sleeve and the second sleeve.

The method may include anchoring a distal end of the rod to the bone.The method may include applying a tension to the rod. The method mayinclude anchoring a proximal end of the rod to the bone.

The method may include expanding a bone support at one end of the rod.

The apparatus and methods of the invention will be described inconnection with embodiments and features of an illustrative bone repairdevice and associated hardware and instrumentation. The device andassociated hardware and instruments will be described now with referenceto the FIGS. It is to be understood that other embodiments may beutilized and structural, functional and procedural modifications may bemade without departing from the scope and spirit of the presentinvention. It will be understood that features shown in connection withone or more of the embodiments may be practiced in accordance with theprinciples of the invention along with features shown in connection withother embodiments.

FIG. 1 shows illustrative rotary-rigid rod 100. Rod 100 may includeouter sleeve 140 and inner sleeve 150. Inner sleeve 150 may have alength that is longer, shorter or substantially the same as the lengthof outer sleeve 140. The sleeves may be constructed of metal, polymer,composite or other suitable material. In some embodiments, the sleevesmay be constructed from Nitinol tube. Void features, such as holes andslots, some of which are shown and described herein, may be provided bylaser cutting or any other suitable method.

Outer sleeve 140 may include proximal end 142 and distal end 144. Innersleeve 150 may include proximal end 152 and distal end 154. Outer sleeve140 may include center section 146. Inner sleeve 150 may havecorresponding center section 156 (shown in FIG. 2). Rotary-rigid rod100, in the configuration shown in FIG. 1, may have longitudinal axisL₁. In some embodiments, rotary-rigid rod 100 may have an essentiallyannular cross section that is substantially perpendicular to axis L₁.Proximal end 142 and proximal end 152 may include, respectively,adjustment flanges 160 and 170. Adjustment flanges 160 and 170 may beused to adjust sleeves 140 and 150 relative to each other incircumferential direction C or -C about axis L₁.

FIG. 2 shows a proximal portion of rotary-rigid rod 100. Inner sleeve150 is shown substantially flush and coaxially aligned with outer sleeve140. Inner sleeve 150 may include a central longitudinal void or may besolid, essentially solid or porous. Inner sleeve 150 may rotate freelywithin outer sleeve 140.

Outer sleeve 140 may include outer holes 241 a, 241 b and 241 c,collectively referred to henceforth as outer holes 241. Inner sleeve 150may include inner holes 251 a, 251 b and 251 c, collectively referred tohenceforth as inner holes 251. Outer holes 240 and inner holes 250 maybe aligned or partially aligned when inner sleeve 150 is in one or morerotational positions with respect to outer sleeve 140.

While only a few of holes shown in FIG. 2 are labeled, it should beapparent that numerous holes of this type may be a part of rod 100. Theholes may include mesh-like cells that are configured to engage ananchoring device.

In some embodiments, rod 100 may include corresponding holes in distalends of sleeves 140 and 150.

Outer sleeve center section 146 may include outer ribs 242 a, 242 b and242 c, collectively referred to henceforth as outer ribs 242. Innersleeve center section 156 may include inner ribs 252 a, 252 b and 252 c,collectively referred to henceforth as inner ribs 252.

FIG. 3 shows outer sleeve 140 and inner sleeve 150 in an alignedconfiguration. In the aligned configuration, outer ribs 242 are alignedin circumferential direction C with inner ribs 252. Inner ribs 254,opposite inner ribs 252, are aligned with outer ribs 244, opposite outerribs 242. Outer ribs 242 and 244 may be circumferentiaily separated fromeach other by longitudinal members 246 and 248. Inner ribs 252 and 254may be circumferentially separated from each other by longitudinalmembers 256 and 258.

Angle α defines the circumferential extent of member 256. Angle α mayhave any suitable magnitude. For example, angle α may range from afraction of a degree to almost 180 degrees. In some embodiments, angle αbe about 90 degrees. Corresponding angles define the circumferentialextent of members 246, 248 and 258. In some embodiments, one or more ofthe angles corresponding to angle α may have a magnitude that isdifferent from that of angle α.

Angle β defines the circumferential separation between members 256 and258. Angle β may have any suitable magnitude. For example, angle β mayrange from a fraction of a degree to almost 180 degrees. In someembodiments, angle β may be about 90 degrees. A corresponding angledefines the circumferential separation between members 246 and 248. Insome embodiments, one or more of the angles corresponding to angle β mayhave a magnitude that is different from that of angle β.

Different magnitudes of angles α and β, and the corresponding angles,may produce in each of sleeves 140 and 150 different bending propertiesalong axis L₁. When the sleeves are rotated about axis L₁ relative toeach other, rod 100 may exhibit different bending properties based onthe different angular magnitudes.

For example, outer ribs 242 and 244 permit outer sleeve 140 to bendalong axis L₁ (about axis L₂) in the direction of either outer ribportion. Inner ribs 252 and 254 permit inner sleeve 150 to bend alongaxis L₁ (about axis L₂) in the direction of either inner rib portion.

To the extent that inner ribs and outer ribs are non-aligned with eachother, rod 100 may exhibit resistance to bending along axis L₁.

Increased thickness t₀ of longitudinal members 246 and 248 may increasethe bending resistance of outer member 140 along axis L₁ about axis L₂.Increased thickness t_(i) of longitudinal members 256 and 258 mayincrease the bending resistance of inner member 150 along axis L₁ aboutaxis L₂.

FIGS. 4 and 5 show heights h₀ and h_(i) of ribs 242 and 252,respectively. Ribs 242 and 252 may be spaced apart by spacings s_(o) ands_(i), respectively. Relatively greater or lesser ratios h_(o):s_(o) andh_(i):s_(i) may decrease or increase, respectively, the bendingresistances of sleeves 140 and 150.

One or more of longitudinal members 246, 248, 256 and 258 may include acomposition or material that provides a relatively greater or lesserdegree of bending resistance along axis L₁ about axis L₂. Suitablecompositions or materials may include implantable materials such asmetals, polymers, composites and any other suitable materials.

One or more of longitudinal members 246, 248, 256 and 258 may include astructure or microstructure that provides a relatively greater or lesserdegree of bending resistance along axis L₁ about axis L₂. Suitablestructure or microstructure may include: sinter, kerfs, cuts, cells,perforations, holes, patterns, helical paths, cells, slots, tapers,angled cuts and any other suitable structure or microstructure.

Properties such as angle α, angle β, thickness t_(o), thickness T_(i),height h_(o), height h_(i), separation s_(o), separation s_(i), ratioH_(o):s_(o), ratio h_(i):s_(i), composition or material, structure ormicrostructure and other suitable properties may vary along axis L₁.

FIG. 6 shows inner sleeve 150 rotated by angle γ relative to outersleeve 140. Inner ribs 252 are now aligned with longitudinal member 246.Outer member 246 may thus provide resistance to a bending moment aboutaxis L₃. Longitudinal member 248 may provide corresponding resistance onthe opposite side of rod 100. Longitudinal members 256 and 258 maysimilarly provide resistance to bending about axis L₂. When γ is at ornear 0°, bending resistance of rod 100 along L₁ about L₂ will berelatively greater. When γ is at or near 90°, bending resistance of rod100 will be relatively lesser.

FIG. 7 shows portions of outer sleeve 140 and inner sleeve 150 inperspective view when γ is slightly greater than 0°.

FIG. 8 shows rod 100 when γ is at or near 0°, bending upon delivery tointramedullary space IS in bone 3. Bone B includes mid-shaft fracture F.Angled delivery tube 800 is present in angled access hole H in bone B.Outer sleeve 150 and inner sleeve 140 are aligned so that rod 100 canbend about axis L₂. (It will be appreciated that axes L₂ and L₃ are notfixed longitudinally along axis L₁.)

After placement in intramedullary space IS, outer sleeve 140 and innersleeve 150 may be rotated such that γ is at or near 90° to provide rod100 with bending resistance. In some embodiments, the rotation mayprovide rod 100 with rigidity.

In some embodiments, rod 100 may be anchored after setting γ at adesired value. Rod 100 may anchor distal fracture F by fastening anchorsin holes 802 at distal ends 144 and 154 of rods 140 and 150,respectively. Rod 100 may anchor proximal fracture F by fasteninganchors in holes such as 240 and 250 (shown in FIG. 2) in proximal ends142 and 152 of outer and inner sleeves 140 and 150, respectively.

Anchors such as screws that penetrate an outer and an inner hole secureouter sleeve 140 relative to inner sleeve 150 and prevent the sleevesfrom rotating out of alignment. Any suitable type of anchor may be used.

Compression or tension may be applied across fracture F between thedistal and proximal fastenings. The tension may be applied by apractitioner after the distal anchors are placed. Rod 100 may includeone or more elastic sections. An elastic section may apply a compressiveor a tensile force between proximal and distal anchors of rod 100. Thetensile force may be applied across fracture F by anchoring rod 100 suchthat the elastic section is in compression. The compressive force may beapplied across fracture F by anchoring rod 100 such that the elasticsection in tension.

In some embodiments, adjustment flanges 160 and 170 may be set relativeto each other to prevent sleeves 140 and 150 from rotating out ofalignment. The setting may be based on inter-threading, cooperatingkeyed members, a keyed or mating outer sleeve, a pin or any othersuitable mechanism.

Setting elements may be integrated into rod 100 at proximal or distalends of rod 100 or anywhere along the length of rod 100. The settingelements may be separate from rod 100. The setting elements may includeone or more of a threaded nut, a sect screw, a cotter pin, a crimp, aswage, a morse taper and any other suitable mechanical interface ormechanism.

FIG. 8 shows holes 802 in distal end 144 of outer sleeve 140.

FIG. 9 shows that holes 802 may pass through wall thickness w_(o) ofdistal end 144. One or more of holes 802 may be tapered at angle δ_(o)relative to normal direction N_(o). One or more of holes 802 may have aradius r_(o). Two or more holes 802 may be longitudinally spaced apartby distance d_(o). Two or more of holes 802 may be circumferentiallyspaced apart by arc length c_(o). Two or more of holes 802 may be offsetfrom longitudinal member 246 centerline CL_(o) by arc length η_(o). Oneor more of parameters w_(o), δ_(o), r_(o), d_(o), c_(o), η_(o), and anyother suitable parameters, may be configured to cooperate with one ormore types of anchors. One or more of parameters w_(o), δ_(o), r_(o),d_(o), c_(o), η_(o), and any other suitable parameters, may beconfigured to cooperate with one or more types of anchors and one ormore of corresponding parameters w_(i), δ_(i), r_(i), d_(i), c_(i),η_(i) (shown in FIG. 10).

FIG. 10 shows holes 1002 in wall thickness w_(i) of distal end 154. Oneor more of holes 1002 may be tapered at angle δ_(i) relative to normaldirection N_(i). One or more of holes 1002 may have a radius r_(i). Twoor more holes 802 may be longitudinally spaced apart by distance d_(i).Two or more of holes 1002 may be circumferentiaily spaced apart by arclength c_(i). Two or more of holes 1002 may be offset from longitudinalmember 256 centerline CL_(i) by arc length η_(i). One or more ofparameters w_(i), δ_(i), r_(i), d_(i), C_(i), η_(i), and any othersuitable parameters, may be configured to cooperate with one or moretypes of anchors. One or more of parameters w_(i), δ_(i), r_(i), d_(i),c_(i), η_(i), and any other suitable parameters, may be configured tocooperate with one or more types of anchors and one or more ofcorresponding parameters w_(o), δ_(o), r_(o), d_(o), c_(o), η_(o) (shownin FIG. 9).

One or more of holes 240 and 250 (shown in FIG. 2) may have one or moreparameter or feature that is similar to one or more of the parametersand features discussed in connection with holes 802 and 1002.

FIG. 11 shows outer sleeve 140 and inner sleeve 150 with angle γ (shownin FTG. 6) at approximately 0°. Outer holes 802 are offset fromlongitudinal member 246 (shown in FIG. 3) center line CL_(o) by arclength η_(o). Inner holes 1002 are offset from longitudinal member 256(shown in FIG. 3) centerline CL_(i) by arc length η_(i).

One or more of holes 240, 340, 802 and 1002 may have any suitable shape.Each of proximal and distal ends of outer sleeve 140 and inner sleeve150 may include holes of different sizes, parameters and features.

Inner and outer holes may be sized or shaped differently to reduce orrelieve angular stress between sleeve 140 and sleeve 150 when sleeves140 and 150 are angularly locked relative to each other.

FIG. 12 shows rod 100 in intramedullary cavity IS′ within bone B′, whichmay be a femur or other long bone. Bone B′ is fractured at fracture F′.Delivery cannula 1200 may provide a curved entry path into cavity IS′through hole H′ in bone B′.

Delivery cannula 1200 may be used to rotate outer sleeve 140 relative toinner sleeve 150 to make rod 100 rigid or partially rigid. For example,cannula 1200 may engage the proximal end of outer sleeve 140. A controlshaft (not shown) may extend through cannula 1200 and engage innersleeve 150. The control shaft may rotate inner sleeve 150 relative toouter sleeve 140. The control shaft and cannula 1200 may then bedisengaged from rod 100.

Anchors 1202 lock outer sleeve 140 and inner sleeve 150 rotationallywith respect to each other. Anchors 1202 also secure rod 100 to bone B′.

In some embodiments, cannula 1200 may be disengaged after the inner andouter sleeves are rotationally locked. In some embodiments, cannula 1200may be disengaged after the inner and outer sleeves are anchored to boneB′.

In some embodiments, the rod inner or outer sleeves may include morethan one pair of longitudinal members. For example, an inner or outersleeve may include two pairs of longitudinal members.

FIG. 13 shows illustrative cut-pattern 1300 for a sleeve such as outersleeve 140 (shown in FIG. 1). Pattern 1300 may be a laser-cut pattern.Pattern 1300, which is shown flat for illustration, may be cut in acylindrical tube to provide compression relief on one side of the tubeand relief on the other side of the tube. Pattern 1300 may include cutarrangement 1302 having length L₂. Pattern 1300 may include cutarrangement 1304 having length L₂. Lengths L₁ and L₂ may be any suitablelength and may be the same as each other or different from each other.Regions 1306 and 1308 may correspond to longitudinal members such as 246and 248 (shown in FIG. 3), respectively.

FIGS. 14 and 15 illustrate principles of an intramedullary rod thatincludes an inner elongated member and an outer tubular member. The rodmay be fixed in a rigid state that includes one or more straightsections and one or more curved sections.

FIG. 14 shows schematically illustrative segment 1400 that may be one ofa chain of segments (not shown) in an inner elongated member of anintramedullary rod. Segment 1400 may have proximal end 1402 that isspaced apart from distal end 1404. Longitudinal axis Ls may extend atleast from proximal end 1402 through distal end 1404. Pivot axis 1406 atproximal end 1402 and pivot axis 1408 at distal end 1404 are axes aboutwhich segment 1400 may move relative to a proximal neighboring segmentand a distal neighboring segment, respectively.

Projection P_(dp) is the projection of distal pivot axis 1408 ontoproximal end 1402. Distal pivot axis 1408 is offset, about axis Ls, fromproximal pivot axis 1406, by angle φ. φ may be any suitable angle fromabout 0° to about 90°.

An intramedullary rod may include the segment chain and an outer sleeve.The segment chain may be placed inside the outer sleeve. The outersleeve may be provided with stress relief features that are distributedalong the length and circumference of the sleeve. In a first relativeorientation of the chain and the outer sleeve, the stress relieffeatures may align with one or both of the pivot axes and the rod may bebendable about the aligned axes.

In a second relative orientation of the chain and the outer sleeve, thestress relief features may be nonaligned with respect to one or both ofthe pivot axes and the rod may be rigid about the nonaligned axes andcurved based on curvature (not shown) within segment 1402 along axis Ls.The curvature may be any suitable curvature.

FIG. 15 shows schematically illustrative segment 1500 that may be one ofa chain of segments (not shown) in an inner elongated member of anintramedullary rod. Segment 1500 may have proximal end 1502 that isspaced apart from distal end 1504. Longitudinal axis L_(t) may extend atleast from proximal end 1502 through distal end 1504. Pivot axis 1506 atproximal end 1502 and pivot axis 1508 at distal end 1504 are axes aboutwhich segment 1500 may move relative to a proximal neighboring segmentand a distal neighboring segment, respectively.

Distal pivot axis 1508 is offset, about transverse axis L_(tt), fromproximal pivot axis 1506, by angle ρ. ρ may be any suitable angle fromabout 0° to about 90°. A chain of segments such as 1500, along with anouter sleeve with suitable stress relief, may be used to provide anintramedullary rod that is flexible in a first configuration, butrigid—and curved-—in a second configuration. The rod may be rigid andcurved by angle ρ in conjunction with any curvature that may be presentin segment 1500 along axis L_(t).

Compound segments may have proximal and distal pivot axes that areoffset contemporaneously by an angle such as φ (shown in FIG. 14) and anangle such as ρ.

An inner elongated member of an intramedullary rod may include segmentssuch as 1400, 1500, compound segments, and any suitable combination thatare embodied as separate articulating chain links. An inner elongatedmember of an intramedullary rod may include segments such as 1502, 1504and compound segments that are embodied as adjacent portions of aunitary member, such as one formed from a laser-cut tube. The segmentsmay be distributed along the rod to provide flexibility for insertioninto a bone and straight or curved rigid sections to distributestiffness in conformance with bone anatomy. One or more of the segmentsthat provide curved rigid support may be used in conjunction withapparatus for providing straight rigid support.

FIGS. 16-21 show illustrative features of embodiments that may includerod sections that may have flexible and rigid curved or bent states.

FIG. 16 shows illustrative rod 1600 in collarbone B_(c). Rod 1600 mayhave one or features in common with rod 100. Rod 1600 may include one ormore straight sections, such as section 1602. Rod 1600 may include oneor more curved sections, such as sections 1604, 1606 and 1608. Bonesupport 1610 may extend from distal end 1612 of rod 1600. Bone support1610 may be fixed to one or more bone fragments (not shown) inmetaphysical region M or epiphyseal region E of bone Bc using anysuitable anchors (not shown).

Rod 1600 may include outer tubular member 1614. Rod 1600 may include aninner elongated member (not shown) that is disposed inside outer tubularmember 1614. The inner elongated member may include segments that areconfigured to bend relative to neighboring segments along one or morepivot axes.

Outer tubular member 1614 may have stress relief features (not shown)that are distributed to cooperate with one or more of the pivot axes toallow rod 1600 to flex during insertion through a bone access hole (notshown) in bone B_(c). The bone access hole may be at an angle withrespect to axis LBC of bone B_(c). Outer tubular member 1614 may haverigid features (not shown) that are distributed to interfere with one ormore of the pivot axes. Rotation of outer tubular member 1614 relativeto the inner elongated member may cause rod 1600 to become rigid in acurved or bent configuration to provide mechanical support to differentportions of bone B_(c).

FIG. 17 shows illustrative rod 1700, which may have one or more featuresin common with rod 1600. Rod 1700 may include bone support 1710 forsupporting one or more bone fragments at a distal end of bone B_(c). Rod1700 may include bone support 1710 for supporting one or more bonefragments at a proximal end of bone B_(c). One or more of bone supports1710 and 1720 may have one or more features in common with bone support1610 (shown in FIG. 16).

Rod 1700 may include outer tubular member 1714. Rod 1700 may include aninner elongated member (not shown) that is disposed inside outer tubularmember 1714. The inner elongated member may include segments that areconfigured to bend relative to neighboring segments along one or morepivot axes.

Rod 1700 may include one or more straight sections such as section 1702.Rod 1700 may include one or more curved or bent sections such assections 1704, 1706 and 1708.

FIG. 18 shows illustrative inner elongated member 1800. Inner elongatedmember 1800 may include segments 1802. Segments 1802 may be connected bylinkages 1804. Exemplary segment 1806 will be discussed in connectionwith FIG. 19.

FIG. 19 shows exemplary segment 1806. Segment 1806 may include body1808. Segment 1806 may include male linkage member 1808 and femalelinkage member 1810 for linkage to neighboring segments 1802 (shown inFIG. 18). Body 1808 may include clearances, such as clearances 1814,1816 and 1818, to reduce interference between segment 1806 andneighboring segments 1802.

Male linkage member 1808 may define pivot axis L_(m) for articulationwith neighboring segment 1801 (shown in FIG. 18). Female linkage member1812 may define pivot axis L_(f) for articulation with neighboringsegment 1803. Pivot axes L_(m) and L_(f) are oblique and define twodifferent bending axes for inner elongated member 1800. Thecorresponding outer tubular sleeve may be configured, at a first angularposition relative to inner elongated member 1800, to permit bendingabout one or both of pivot axes L_(m) and L_(f). The outer tubularsleeve may be configured, at a second angular position relative to innerelongated member 1800, to prevent bending about one or both of pivotaxes L_(m) and L_(f).

FIG. 20 shows angle ρ′, which corresponds to angle ρ (shown in FIG. 15).Angle ρ′, along with any curvature in the body of segment 1806, may bethe basis for rigid curvature when the rod is in its rigid state.

FIG. 21 shows illustrative cut-pattern 2100 for an outer tubular membersuch as 1614 (shown in FIG. 16). Pattern 2100 may be a laser-cutpattern. Pattern 2100, which is shown flat for illustration, may be cutin a cylindrical tube to provide stress relief in different directionsthat is distributed along axis L_(MD) (shown projected onto cut-pattern2100) of the outer tubular member.

Patterns 2102 and 2104, which may be similar to patterns 1302 and 1304(shown in FIG. 13), may allow bending about a first axis that is normalto axis L_(MD) (as shown, prior to deformation). Patterns 2102 and 2104may be separated by rigid section 2106. Patterns 2108 and 2110 may allowhelical bending about axis L_(MD) (as shown, prior to deformation). Thehelix allowed by pattern 2108 may have an opposite sense of rotationfrom that of pattern 2110.

Pattern 2112 may allow a high degree of bending about a second axis thatis normal to axis L_(MD) (as shown, prior to deformation). Pattern 2114may allow a high degree of bending about a third axis that is normal toaxis L_(MD) (as shown, prior to deformation).

Patterns 2116 and 2118, which may be similar to cut patterns 2102 and2104, may allow bending about a fourth axis that is normal to axis LMD(as shown, prior to deformation). The fourth axis may be angularlyoffset, about axis LMD, with respect to the first axis (defined by cutpatterns 2102 and 2104).

Processes in accordance with the principles of the invention may includeone or more features of the processes illustrated in FIG. 22. Theprocesses may involve the use of one or more of the apparatus shown anddescribed herein. Some steps of the processes may be performed in aninpatient setting. Some steps of the processes may be performed in anoutpatient setting.

The steps of the processes may be performed in an order other than theorder shown, and described herein. Some embodiments of the invention mayomit steps shown and described in connection with the illustrativemethods. Some embodiments of the invention may include steps that arenot shown and described in connection with the illustrative methods.

FIG. 22 shows illustrative steps of process 2200 for repairing afracture. At step 2202, a practitioner may drill an access hole at angleto a bone axis. At step 2204, the practitioner may prepare anintramedullary space in the bone to receive a rod. At step 2206, thepractitioner may align inner and outer sleeves of rod to make the rodflexible. At step 2208, the practitioner may insert rod into theintramedullary space. At step 2210, the practitioner may rotate theinner sleeve relative to the outer sleeve or rotate the outer sleeverelative to the inner sleeve to reduce or eliminate flexibility of therod. At step 2212, the practitioner may fix a rotational offset betweensleeves. The practitioner may fix the rotational offset by actuating amechanism that locks the sleeves with respect to each other, but doesnot necessarily lock the rod to the bone. At step 2214, the practitionermay anchor the rod distal end to the bone. At step 2216, thepractitioner may apply tension to the rod. At step 2218, thepractitioner may anchor the rod proximal end to the bone.

Thus, apparatus and methods for fracture repair have been provided.Persons skilled in the art will appreciate that the present inventioncan be practiced by other than the described embodiments, which arepresented for purposes of illustration rather than of limitation. Thepresent invention is limited only by the claims that follow.

1. An intramedullary rod defining a longitudinal axis and comprising: afirst elongated member disposed within a second elongated member, thefirst elongated member having inner stress relief features and an innerlongitudinal member and the second elongated member having outer stressrelief features and an outer longitudinal member; and an expandable bonesupport extending from an end of one of the first and second elongatedmembers; wherein the elongated members are arranged so that: the rod isbendable when the second elongated member is circumferentially rotatedabout the longitudinal axis to align the inner stress relief featureswith the outer stress relief features; and the rod is rigid when thesecond elongated member is circumferentially rotated about thelongitudinal axis to align the inner longitudinal member with the outerstress relief features.
 2. The intramedullary rod of claim 1 wherein:the expandable bone support is a first expandable bone support; the endis a first end; and a second expandable bone support extends from asecond end of one of the first and second elongated members.
 3. Theintramedullary rod of claim 1 wherein the expandable bone supportextends from a proximal end of the first member and a proximal end ofthe second member.
 4. The intramedullary rod of claim 1 wherein theexpandable bone support extends from a distal end of the first memberand a distal end of the second member.
 5. The intramedullary rod ofclaim 1 wherein: the outer stress relief features correspond to a firstarrangement of slots that are longitudinally spaced from each other; andthe inner stress relief features correspond to a second arrangement ofslots that are longitudinally spaced from each other.
 6. Theintramedullary rod of claim 5 wherein the slots are longitudinallyseparated by ribs.
 7. The intramedullary rod of claim 5 wherein: theinner longitudinal member is a first inner longitudinal member; theouter longitudinal member is a first outer longitudinal member; theslots defined by the inner member are circumferentially separated by thefirst inner longitudinal member and a second inner longitudinal member;and the slots defined by the outer member are circumferentiallyseparated by the first outer longitudinal member and a second outerlongitudinal member.
 8. The intramedullary rod of claim 5 wherein theslots are configured to provide tension relief.
 9. The intramedullaryrod of claim 5 wherein the slots are configured to provide compressionrelief.
 10. The intramedullary rod of claim 1 wherein: the outer stressrelief features correspond to: a first arrangement of slots that arelongitudinally spaced from each other for tension relief; and a secondarrangement of slots that are longitudinally spaced from each other toprovide compression relief, wherein the first and second arrangements ofslots are spaced circumferentially apart from each other; and the innerstress relief features correspond to: a third arrangement of slots thatare longitudinally spaced from each other for tension relief; and afourth arrangement of slots that are longitudinally spaced from eachother to provide compression relief, wherein the third and fourtharrangements of slots are spaced circumferentially apparat from eachother.
 11. The intramedullary rod of claim 1 wherein both the innerstress relief features and the outer stress relief features includesinter.
 12. The intramedullary rod of claim 1 wherein both the innerstress relief features and the outer stress relief features includekerfs.
 13. The intramedullary rod of claim 1 wherein the first andsecond elongated members include, respectively, a first and secondanchor receiving feature.
 14. The intramedullary rod of claim 13 whereinthe first and second elongated members are configured to be positionedrelative to each other such that the first and second anchor receivingfeatures are positioned to receive the same anchor.
 15. Theintramedullary rod of claim 14 wherein the first and second anchorreceiving features are distal a first and a second arrangement of slots.16. The intramedullary rod of claim 15 wherein the first and secondelongated members include, respectively, a third and fourth anchorreceiving feature.
 17. The intramedullary rod of claim 16 wherein thethird and fourth anchor receiving features are proximal the first andsecond arrangements of slots. 18 . The intramedullary rod of claim 1further comprising a locking mechanism that includes: a first adjustmentflange attached to the first elongated member; a second adjustmentflange attached to the second elongated member; and a setting elementthat is configured to prevent relative rotation about the longitudinalaxis of the first elongated member with respect to the second elongatedmember.
 19. The intramedullary rod of claim 18 wherein one of the firstand second adjustment flanges is threaded.
 20. The intramedullary rod ofclaim 1 wherein the first elongated member includes a first fixed curveand the second elongated member includes a second fixed curve.
 21. Theintramedullary rod of claim 1 wherein, when the rod is rigid, the rodincludes one or more straight sections.
 22. The intramedullary rod ofclaim 1 wherein, when the rod is rigid, the rod includes one or morecurved sections.
 23. The intramedullary rod of claim 1 wherein, when therod is rigid, the rod includes one or more straight sections and one ormore curved sections.
 24. The intramedullary rod of claim 1 wherein theexpandable bone support is configured to support one or more bonefragments.
 25. The intramedullary rod of claim 1 wherein the innermember can rotate freely within the outer member.
 26. The intramedullaryrod of claim 1 wherein: the inner member has a first length; the outermember has a second length; and the first length is shorter than thesecond length.
 27. The intramedullary rod of claim 1 wherein: the innermember has a first length; the outer member has a second length; and thefirst length is longer than the second length.
 28. The intramedullaryrod of claim 1 wherein: the inner member has a first length; the outermember has a second length; and the first length is substantially thesame as the second length.
 29. The intramedullary rod of claim 1 whereinthe inner member is essentially solid.
 30. The intramedullary rod ofclaim 1 wherein the inner member defines a central longitudinal void.31. The intramedullary rod of claim 1 wherein the inner member isporous.
 32. The intramedullary rod of claim 1 wherein the inner memberincludes one or more elastic sections.
 33. The intramedullary rod ofclaim 1 wherein the outer member includes one or more elastic sections.34. The intramedullary rod of claim 1 wherein the inner member isdisposed coaxially within the outer member.
 35. The intramedullary rodof claim 1 wherein the inner member is disposed within the outer membersuch that the inner member is substantially flush with the outer member.36. The intramedullary rod of claim 1 wherein the thickness of the innermember varies along a longitudinal axis defined by the inner member. 37.The intramedullary rod of claim 1 wherein the thickness of the outermember varies along a longitudinal axis defined by the outer member.38-71. (canceled)